JPH10302384A - Disk driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain the vibration due to eccentricity, to stabilize the precision of reading data, to reduce a re-try processing and to improve processing efficiency by detecting the eccentric quantity of a disk at the reference rotating speed and executing the rotation control of a spindle motor at the double speed determined in accordance with the eccentric quantity. SOLUTION: When a disk D is installed, the spindle motor 6 is rotated at the double reference speed with a system controller 10, a tracking servo is turned off and an optical pickup 1 is fixed in the radial direction. A tracking error signal TE is generated from the output signal of a photo-detector 5 and sent to a traverse counter 19 with a RF amplifier 9. When eccentricity exists in the disk D, the number of traversed track is counted with the traverse counter 19. The pulse from a spindle FG equivalent to one rotation of the disk D is counted with the system controller 10, and the eccentric quantity is calculated based on the number of traversed track received from the traverse counter 19 for the duration.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk drive capable of detecting the eccentricity or eccentricity of a disk and controlling the rotational speed of the disk in accordance with the eccentricity or eccentricity. .

[0002]

2. Description of the Related Art Recently, a disk-shaped recording medium such as a CD-ROM (hereinafter referred to as a disk) has been known as a recording medium for various data and programs used in personal computers and the like. Such a disk is rotated at a predetermined speed after being mounted on a disk drive device, and reads various data and programs recorded on a signal surface by an optical pickup, or reads the type of the disk (for example, MO ... Magnet). O
ptical, MD ... Mini Disc, DVD-RAM ...
Digital Versatile Disc-Random Access Memory etc.)
In some cases, recording can be performed.

By the way, when data such as data recorded on the CD-ROM is read, the disk is rotated at a speed higher than a standard speed (1 × speed) for the purpose of improving the reading efficiency. There is known a disk drive device capable of performing such operations. In such a disk drive device, the rotational speed of the disk is set to a standard speed (200
About 500 rpm), for example, by performing a high-speed rotation such as 4 times speed, 6 times speed, and 8 times speed,
The reading efficiency is improved.

[0004]

As described above, the reading efficiency is improved by increasing the rotation speed of the disk at the time of reading or recording, but when the disk is rotated at a high speed, the deviation of the disk is increased. Core and eccentricity may be a problem. For example, eccentricity means that the center of the center hole of the disk physically coincides with the center of gravity, but the center of the center hole does not coincide with the center of the track (radial or concentric). In addition, the eccentricity means that the center hole of the disk physically matches the center of the track, but the position of the center hole does not match the center of gravity of the disk. In the present specification, the above-described eccentricity and eccentricity are collectively referred to as eccentricity.

[0005] The eccentricity may be caused by, for example, accuracy in manufacturing a disc performed by press working or the like, or an error caused by chucking of a center hole when the disc is loaded into a drive device. There is. When the disk is rotated at a high speed as described above in an eccentric state, for example, 3000 rpm
At a high speed of about m, self-excited vibration having a frequency corresponding to the rotation speed is generated. This vibration is proportional to the amount of eccentricity and the number of rotations of the disk, and has a great effect on a disk drive device rotating at high speed.

First, when a disk is loaded and chucked in a disk drive, the type of the disk is read by the disk drive in order to read out the TOC (Table Of Contents) recorded on the inner track. Rotation is started at a rotational speed (for example, 4 ×, 6 ×, 8 ×, etc.) that is set for each case, but if there is eccentricity at this point, vibration occurs. If this vibration is transmitted to the outside of the disk drive device, it will cause discomfort to the user. In addition, when the vibration is large, the tracking servo may not be able to follow, and thus it becomes difficult to read data from the disk, and a read error tends to occur. As a result, if the retry of the error process is frequently performed, the efficiency of various processes that should be performed is deteriorated. Further, when the eccentricity is large and the vibration is large, the drive device and the disk itself may be damaged.

[0007]

SUMMARY OF THE INVENTION In order to solve such a problem, the present invention provides an eccentricity detecting device for detecting the amount of eccentricity of a disk which is mounted on the disk drive and is rotatable. And a rotation speed setting unit configured to set the rotation driving speed of the disk to a predetermined multiple speed in accordance with the eccentricity detected by the eccentricity detection unit.

According to the present invention, the present invention detects the amount of eccentricity when the disk is chucked, and sets the rotational speed of the disk during recording / reproducing according to the amount of eccentricity. In addition, vibration due to eccentricity can be reduced. Further, the burden on the tracking servo control can be reduced.

[0009]

Embodiments of the present invention will be described below. FIG. 1 is a block diagram illustrating a configuration of a main part of the disk drive device according to the present embodiment. The disk drive device according to the present embodiment uses a CD as a disk, for example.
-The description will be made assuming that the ROM and the audio CD are supported. When the disk D shown in this figure is inserted into the disk drive by a loading mechanism (not shown), it is placed on the turntable 7 and the center hole HD is chucked and loaded by the chucking mechanism 7a. . During the reproducing operation, the optical disc 1 is rotated at a constant linear velocity (CLV) by the spindle motor 6, and
Of the data recorded on the signal surface is read.

The optical pickup 1 includes a laser diode 4 serving as a light source of laser light, an optical system including a deflection beam splitter and an objective lens 2, a photodetector 5 for detecting laser light reflected on the disk D, and the like. It is configured. Here, the objective lens 2 is movably supported by the biaxial mechanism 3 in the tracking direction and the focus direction.

The laser light reflected from the disk D by the reproducing operation of the disk drive device is detected by the photodetector 5 as a light receiving current. And
This light receiving current is output to the RF amplifier 9 as an information signal read from the disk D. The RF amplifier 9 includes a current-voltage conversion circuit, an amplification circuit, and a matrix operation circuit (R
F matrix amplifier) and the like, and generates a necessary signal based on a signal from the photodetector 5. For example, an RF signal which is reproduction data, a push-pull signal PP for servo control, a focus error signal FE, a tracking error signal TE, a pull-in signal P which is a so-called sum signal.
I and the like are generated.

Various signals generated by the RF amplifier 9 are 2
The value is supplied to the value conversion circuit 11 and the servo processor 14. That is, the reproduced RF signal from the RF amplifier 9 is converted to a binarized circuit 11
To push-pull signal PP and focus error signal F
E, the tracking error signal TE, and the pull-in signal PI are supplied to the servo processor 14.

The reproduced RF signal obtained by the RF amplifier 9 is 2
The signal is binarized by the value conversion circuit 11 to be a so-called EFM + signal (8-16 modulated signal), which is supplied to the decoder 12. The decoder 12 decodes the EFM signal (EFM demodulation and error correction, CD-ROM decoding, etc.) using a reproduction clock obtained by injecting the EFM signal into the PLL. The decoded data is supplied to a host computer (not shown) via the interface unit 13. Further, disk rotation speed information is obtained from a reproduction clock synchronized with the EFM signal. This disc rotation speed information is the relative speed between the laser spot output from the optical pickup 1 and the track.

In this embodiment, a traverse counter 19 is provided, and the tracking error signal TE obtained by the RF amplifier 9 is also supplied to the traverse counter 19. The traverse counter 19 generates a traverse pulse from the input tracking error signal TE. The traverse pulse will be described later with reference to FIG.
This will be described in detail.

The spindle error signal SPE generated by the servo processor 14 is
, Where a spindle servo signal is generated based on the spindle error signal SPE.

The servo processor 14 generates various servo drive signals for focus, tracking, sled, and spindle from the focus error signal FE, the tracking error signal TE, the push-pull signal PP, and the like from the RF amplifier 9 to execute a servo operation. . That is, a focus drive signal FDR and a tracking drive signal are generated in accordance with the focus error signal FE and the tracking error signal TE, and supplied to the two-axis driver 16.

The servo processor 14 generates a thread drive signal based on, for example, a thread error signal obtained from a low-frequency component of the tracking error signal TE or an access execution control from the system controller 10 and supplies the thread drive signal to the thread driver 15. . The thread driver 15 responds to the thread drive signal by the thread mechanism 8.
Drive. The sled mechanism 8 is a mechanism for moving the entire optical pickup 1 in the radial direction of the disc. The sled driver 15 drives the sled mechanism 8 in accordance with a sled drive signal, so that the optical pickup 1 is appropriately slid.

The servo processor 14 also controls light emission driving of the laser diode 4 in the optical pickup 1. The laser diode 4 is driven by a laser driver 18 to emit laser light. The servo processor 14 generates a laser drive signal for executing laser emission at the time of reproduction or the like based on an instruction from the system controller 10, and outputs the laser drive signal. 18. In response, the laser driver 18 drives the laser diode 4 to emit light.

The biaxial driver 16 includes, for example, a focus coil driver 16a and a tracking coil driver 16b. The focus coil driver 16a supplies the drive current generated based on the focus drive signal FDR to the focus coil of the biaxial mechanism 3 to drive the objective lens 2 in the direction of moving toward and away from the disk surface. Tracking driver 16
b drives the objective lens 2 in the disk radial direction by supplying a drive current generated based on the tracking drive signal to the tracking coil of the biaxial mechanism 3. As a result, a tracking servo loop and a focus servo loop by the optical pickup 1, the RF amplifier 9, the servo processor 14, and the two-axis driver 16 are formed.

Various operations such as servo and decoding as described above are controlled by a system controller 10 including a microcomputer and the like. For example, operations such as reproduction start, end, track access, fast forward reproduction, and fast reverse reproduction are realized by the system controller 10 controlling the operation of the optical pickup 1 via the servo processor 14.

The system controller 10 can set reference speed information for the servo processor 14,
The servo processor 14 compares the set reference speed information with the rotation speed information from the decoder 12 to generate a spindle error signal SPE. Further, by changing the setting of the reference speed information, the CLV speed can be controlled to, for example, 2 × speed, 4 × speed, 6 × speed,. Further, in the present invention, the system controller 10 performs control to set a predetermined double speed as a drive rotation speed during reproduction with respect to the disk D based on the amount of eccentricity of the disk D detected as described later.

In the disk drive device according to the present embodiment having the above configuration, the eccentric amount of the disk D in the chucked state is detected, and the maximum eccentricity set in advance for each disk type in accordance with the eccentric amount is detected. It is configured to variably set the disk rotation speed at the time of performing the disk reproduction operation within the speed range where the speed is the maximum rotation speed. Therefore, a method of detecting the amount of eccentricity of a disk according to the present embodiment will be described first.

FIG. 2 is a schematic diagram for explaining the relationship between the track pitch of the disk D and the traverse pulse.
FIG. 2A is a diagram illustrating a groove and a land in a state where a part of the disk D is enlarged and formed in a cross section in a radial direction, and FIG. 2B is a diagram illustrating a radial direction with respect to the disk illustrated in FIG. FIG. 2C schematically shows a tracking error signal obtained when the optical pickup is moved, and FIG. 2C shows a traverse pulse generated by the traverse counter 20 based on the tracking error signal.

As shown in FIG. 2A, when the disk D is viewed in cross section along the radial direction, the lands 30 and the grooves 31 are located alternately. For example, in this case, the groove 31 is a track on which data pits are recorded. Therefore, as shown in FIG.
The distance between the respective center positions 31 is the track pitch tp. Here, the objective lens 2 was irradiated with the laser beam while moving as shown in a movement locus 33 of FIG. 2A as a relative positional relationship with respect to the disk surface, that is, while moving across the disk radial direction. Then, it is known that a waveform shown in FIG. 2B is obtained as the tracking error signal TE. That is, a sinusoidal waveform is obtained in which zero level is obtained when the center of the land 30 and the groove 31 is irradiated with the laser beam.

The traverse counter 19 of the present embodiment receives a tracking error signal TE and outputs, for example, a pulse signal which is compared with a level 0 as a reference, as a comparator pulse, and a pulse of this comparator pulse. And a counter capable of counting the number. For example, when the tracking error signal TE shown in FIG. 2B is compared by the comparator of the traverse counter 19, a traverse pulse having a pulse waveform shown in FIG. 2C is obtained. This figure 2
Comparing the waveform shown in (c) with the cross-sectional view of the disk shown in FIG. 2 (a), it can be seen that one cycle of the traverse pulse corresponds to a state of crossing one track. Therefore,
The number of H-level or L-level pulses of the traverse pulse corresponds to the number of track crossings. The traverse counter 19 counts, for example, the number of compare pulses, and outputs information on the count value to the system controller 10. System controller 10
Then, the amount of eccentricity of the disk D can be calculated based on the input count value of the compare pulse as described below.

First, in order to calculate the amount of eccentricity, after the disk D is driven to rotate, the focus servo loop is turned on and the tracking servo loop is turned off so that no tracking drive signal is applied. Thus, the movement of the objective lens 2 is fixed in the tracking direction. In this state, for example, each time the disk makes one revolution, the laser beam of the objective lens 2 crosses a certain number of tracks according to the degree of eccentricity. Therefore, at this time, the count value of the traverse pulse obtained by the traverse counter 19 for each rotation cycle corresponds to the disk eccentricity. Therefore, the system controller 10 can calculate the eccentricity of the disk according to the following principle.

FIG. 3 shows a change in the amount of eccentricity of the disk D detected corresponding to one rotation cycle of the disk D. The ordinate indicates the amount of eccentricity x, and the abscissa indicates the rotation angle of the disk D. Is shown. As the eccentric amount x to be calculated by the system controller 10, for example, if an absolute amount (a range of PP (Peak to Peak) in FIG. 3) corresponding to one rotation of the disk D is obtained, it is obtained corresponding to the rotation of the disk 1D. Assuming that the count value of the obtained traverse pulse is N and the track pitch is Tp (see FIG. 2A), x = N × Tp / 2 (PP)... That is, the count value N is 1
Since the number of tracks to be traversed by the rotation is reciprocated, the actual number of traversed tracks according to the eccentricity x is calculated by the count value N / 2. Then, the count value N /
By multiplying 2 by the track pitch tp, eccentricity information can be physically obtained. If the eccentricity x as the amount of deviation based on the 0 level is determined, x = N × Tp / 4 (0−P)... When calculating the amount of eccentricity x, either equation 1 or equation 2 may be used.

Next, an example of the actual processing operation of the system controller 10 in the case of detecting the eccentricity x and setting the rotation speed of the spindle motor at the time of reproduction, for example, will be described with reference to the flowchart shown in FIG. . Here C
The D-ROM is driven to rotate at a maximum speed of 8 times,
The description will be made on the assumption that the audio CD is set to be driven at a maximum speed of 4 ×.

Disk D
Is detected (S001), first, the rotation of the spindle motor 6 is controlled (S002). Here, the spindle motor 6 is controlled to rotate at, for example, a standard speed (for example, 1 × speed), and thereafter, the eccentric amount of the disk D is calculated and rotated at the standard speed until the tracking servo and the thread servo are turned on. Control. By controlling the spindle motor 6 to rotate at the standard double speed, large vibrations when the amount of eccentricity is large can be reduced, so that the disk drive device and the disk D can be protected and safety can be achieved.

When the spindle motor 6 is rotated, the focus servo is turned on next (S003), and the traverse pulse while the spindle FG detects the M wave is counted to detect the count value N (S004). In this case, the number M of the spindles FG is, for example, 12 in one rotation.
For example, when the eccentricity is detected by 1/3 rotation, it is necessary to count how many traverse pulses are detected while the spindle FG detects 4 waves. Good.

In FIGS. 2 and 3 described above, an example in which the amount of eccentricity is calculated in one rotation has been described. However, for example, the count value N obtained when the disk D is rotated in an angle range smaller than 360 ° may also be used. For example, it is possible to calculate by correcting the count value N at the time of one rotation. Therefore, the amount of eccentricity x can be calculated almost accurately by the count value N obtained during 1/3 rotation. Thereby, the time for detecting the amount of eccentricity x can be reduced.

When the count value N of the M wave period is detected,
Using this count value N, the amount of eccentricity x is calculated by applying, for example, the above equations 1 and 2 (S005). Then, flags FLG1 and FLG2 for indicating the amount of eccentricity x are initialized to, for example, “0”. In this flowchart, the flag FLG1
Is set as a flag indicating that the amount of eccentricity x is equal to or more than a predetermined threshold value A described below, and a flag FLG2 is set as a flag indicating that the amount of eccentricity x is equal to or more than a predetermined threshold value B. You have set. Hereinafter, the rotational speed control of the spindle motor 6 corresponding to the eccentric amount x is performed by comparing the eccentric amount x with predetermined threshold values A and B. It should be noted that the threshold value A is C which is driven at a high speed of up to 8 times speed.
The threshold value B is set relatively low corresponding to the D-ROM.
Is set higher than the threshold value A corresponding to an audio CD that is rotationally driven at a maximum speed of 4 times.

First, the eccentric amount x is compared with the threshold value B (S007). When it is determined that the eccentric amount x is equal to or larger than the threshold value B, "1" is set to the flags FLG1 and FLG2 (S008). . If it is determined that the eccentricity x is equal to or smaller than the threshold B, it is further determined whether the eccentricity x is equal to or larger than the threshold A (S009). "1" is set only for FLG1 (S010). Then, the tracking servo loop is turned on (S011), and it is determined whether "1" is set in either the flag FLG1 or the flag FLG2 (S012). If it is determined that "1" is set, the thread is set. The gain band is limited to a predetermined value or less (S013), and the thread servo is turned on (S014). If it is determined that “1” is not set in either the flag FLG1 or the flag FLG2 (S0
12) The thread servo is turned on without limiting the thread gain band to a predetermined value or less (S014).

Here, the flag FLG1 or the flag FLG
The reason why the thread gain band is limited to a predetermined value or less when “1” is set in any one of the two is that the control sensitivity of the thread servo loop is set lower than usual when the eccentricity of the disk D is large. Thus, unnecessary thread operation is reduced to reduce the burden on tracking servo control. Step S002 described above
Thus, the processing described in step S014 is performed with the disk D rotated at the standard speed as described above.

In step S015, the TOC (Tabl
e of Contents) The TOC information is read from the area to determine the disc type. Here, disk D is CD-R
If it is determined that the command is OM, the process proceeds to step S016, and waits for a command input such as, for example, starting up application software or reading data. When the command input is detected (S016), the flag FLG1 is set. It is determined whether or not “1” is set in (S017). When "1" is set in the flag FLG1, control is performed to rotate the spindle motor 6 at, for example, a quadruple speed (S018). If it is determined in step S017 that "1" is not set in the flag FLG1, control is performed to rotate the spindle motor 6 at, for example, 8 times speed (S01).
9). Then, data is read at the double speed set in step S018 or step S019 (S020). In step S018, the speed may be set to a quadruple speed or less, such as a double speed, but in the case of a CD-ROM, the data reading speed is required.

If it is determined in step S015 that the disk D is an audio CD, the flow advances to step S021 to wait for an input of a playback command of, for example, a recorded musical piece. If detected, it is determined whether or not "1" is set in the flag FLG2 (S022). If "1" is set in the flag FLG2, control is performed to rotate the spindle motor 6 at, for example, a double speed (S023). If it is determined in step S022 that "1" is not set in the flag FLG2, control is performed to rotate the spindle motor 6 at, for example, a quadruple speed (S024). Then, step S023 or step S024
The reproduction of the music or the like is performed at the predetermined speed set in (S025). In step S023, the speed of the spindle motor 6 is set to, for example, double speed. For example, since the decoder 12 shown in FIG. 1 is provided with a buffer memory for reproduction data, the reproduction data is stored in this buffer. It will be read from memory. Therefore, only the vibration resistance is inferior and does not affect the normal reproduction processing.

In the flowchart shown in FIG.
The eccentricity x was obtained in step S005 based on the traverse pulse count value N in step S004.
The count value N of the traverse pulse may be directly applied as the eccentric amount information.

As described above, when reading data, the spindle motor can be rotated at a predetermined speed according to the eccentricity x detected in advance at the standard speed. Therefore, unnecessary vibration generated when the amount of eccentricity x is large can be suppressed, so that the data reading accuracy can be stabilized. Further, since unnecessary vibration can be suppressed, the disk drive device and the disk D itself can be protected.

In the present embodiment, a disk drive device that controls the rotation of the spindle motor 6 at a normal speed of, for example, a CD-ROM according to the amount of eccentricity x is used.
In the case of the CR-ROM, for example, a 6-times speed according to the amount of eccentricity has been described. , And a threshold value corresponding to the amount of eccentricity may be set. As described above, the rotation speed with respect to the eccentric amount can be freely set. If it is determined that the amount of eccentricity is considerably large, it is conceivable that the chucking is defective. Therefore, for example, control is performed so as to stop the rotation once, release the chucking mechanism 7a, and chuck the disk D again. May be.

The number of rotations for detecting the amount of eccentricity x is:
Although the standard speed (1 × speed) has been described as an example, the rotation may be any speed other than the standard speed as long as the rotation does not cause large vibration due to eccentricity. Further, in the present embodiment, as an example of a method of detecting the amount of eccentricity x, the spindle motor 6
Although the example in which the number of traverse pulses per rotation number is detected has been described, the eccentricity x may be detected by other methods.

Further, in the present embodiment, a CD-ROM disk drive device compatible with 8 × speed has been described as an example, but a CD-ROM disk drive compatible with 12 × speed, 16 × speed, etc. It is also possible to apply to a drive device. In addition, C shown in the present embodiment as an example
In addition to the D-ROM disk drive, for example, M
The present invention can be applied to disk drive devices such as D, MO, and DVD. Furthermore, in this embodiment, only the case of reproduction is described as an example. However, the disk drive device of the present invention is applied to a recording device, and the rotational speed at the time of recording is increased by a predetermined speed according to the detected eccentricity. Can be set to

[0042]

As described above, the disk drive of the present invention detects the eccentricity of the disk at a predetermined speed lower than the maximum speed, for example, and detects the spindle at a predetermined speed corresponding to the eccentricity. The rotation of the motor can be controlled. Therefore, vibration due to eccentricity can be suppressed to a minimum, so that data reading accuracy can be stabilized. Also, because the band of the thread servo is reduced when eccentricity is detected,
It is possible to perform stable data reading.
By further improving the data reading accuracy,
Retry processing for read errors can be reduced,
Various processes that should be performed can be efficiently performed without performing unnecessary retry processes.
Further, since unnecessary vibration can be suppressed, it is possible to prevent damage to the disk drive device and the disk itself.

Further, since the rotation speed with respect to the eccentricity can be set according to the type of the disk, for example, even in a disk drive device corresponding to a different type of disk, the rotational speed corresponding to the eccentricity is determined for each disk. The most efficient rotation speed can be set.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a main part of a disk drive device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram illustrating a traverse pulse.

FIG. 3 is a schematic diagram illustrating an eccentric amount per one rotation (360 °) of a disk.

FIG. 4 is a flowchart illustrating a process of detecting an eccentric amount and setting a rotation speed during reproduction according to the eccentric amount.

[Explanation of symbols]

D disk, 1 optical pickup, 6 spindle motor, 9 RF amplifier, 10 system controller, 12 decoder, 14 servo processor, 17
Spindle motor driver 17, 19 Traverse counter, D disk, TE tracking error signal

Claims (4)

[Claims] An eccentricity detecting means for detecting an eccentricity of a disk loaded in the disk drive and capable of being driven to rotate; and an eccentricity detected by the eccentricity detecting means,
A rotation speed setting means for setting a rotation drive speed of the disk to a predetermined multiple speed. 2. The disk has a track for signal recording formed along a circumferential direction, and the eccentricity detecting means includes an objective lens for irradiating the disk with laser light. From a tracking error signal obtained in a state in which the position in the tracking direction is fixed and the disk is rotationally driven at a predetermined multiple speed lower than at least a preset maximum multiple speed, the disk is rotated within a predetermined angle within a predetermined period. Traversing track number detecting means for detecting the number of tracks traversed by the laser beam, and eccentricity calculating means capable of calculating the eccentricity of the disk based on the number of traversing tracks detected by the traversing track number detecting means. The disk drive device according to claim 1, wherein the disk drive device comprises: 3. A predetermined double speed lower than the maximum double speed is set to a double speed that does not exceed a predetermined allowable range with respect to a predetermined event caused by eccentricity of the disk during rotation driving. 3. The disk drive according to claim 2, wherein: 4. As a relative positional relationship between the disc and a pickup provided with an objective lens for irradiating the disc with a laser beam, the pickup follows the tracking control and is arranged in a radial direction of the disc. It is assumed that thread servo means for controlling the movement is provided, and according to the eccentricity detected by the eccentricity detecting means,
2. The disk drive device according to claim 1, wherein the thread servo means includes thread servo gain setting means configured to vary a thread servo gain for setting a control sensitivity of the thread servo loop.